A normal suspension device for a wheel of a vehicle will be described with reference to an example of a driven wheel shown in FIG. 26 of Patent Document 1. A rotating drive train of the vehicle is coupled to an output shaft by a universal joint, etc. A tip end of the output shaft is fixed to a wheel disk. Further, a bearing member for rotatably supporting the output shaft is supported via a suspension element and a suspension arm that are disposed on a vehicle body and outside of the wheel.
With this configuration, it is necessary to provide space for disposing the suspension element and the suspension arm, and as a result vehicle design may be restricted, the width of the vehicle increased, and the passenger compartment made smaller.
To address these issues, the present applicant developed the wheel assembly of Patent Document 1. The example shown in FIGS. 1 2 will be used to explain the wheel assembly. A disk and a rim of the wheel are formed from independent components. The disk is coupled to a rotating drive train, and a plurality of short suspension elements is provided between an outer periphery of the disk and an inner periphery of the rim. The suspension elements are positioned at substantially equal distances in the circumferential direction.
According to the above configuration, rotation of the disk is transmitted to the rim and a tire attached to the rim via the plurality of suspension elements. Note that, the tire is sometimes subjected to shock and vibration generated by holes or bumps in the road surface. At these times, suspension elements that happen to be in a raised position soften and absorb the shock and vibration. Since the suspension elements are built into the wheel assembly, there is no need to provide space for disposing a suspension element outside of the wheel.    Patent Document 1: Japanese Patent Application Publication No. JP-A 2002-370503 (FIGS. 1, 2, 26).